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Dougan KE, Deng ZL, Wöhlbrand L, Reuse C, Bunk B, Chen Y, Hartlich J, Hiller K, John U, Kalvelage J, Mansky J, Neumann-Schaal M, Overmann J, Petersen J, Sanchez-Garcia S, Schmidt-Hohagen K, Shah S, Spröer C, Sztajer H, Wang H, Bhattacharya D, Rabus R, Jahn D, Chan CX, Wagner-Döbler I. Multi-omics analysis reveals the molecular response to heat stress in a "red tide" dinoflagellate. Genome Biol 2023; 24:265. [PMID: 37996937 PMCID: PMC10666404 DOI: 10.1186/s13059-023-03107-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
BACKGROUND "Red tides" are harmful algal blooms caused by dinoflagellate microalgae that accumulate toxins lethal to other organisms, including humans via consumption of contaminated seafood. These algal blooms are driven by a combination of environmental factors including nutrient enrichment, particularly in warm waters, and are increasingly frequent. The molecular, regulatory, and evolutionary mechanisms that underlie the heat stress response in these harmful bloom-forming algal species remain little understood, due in part to the limited genomic resources from dinoflagellates, complicated by the large sizes of genomes, exhibiting features atypical of eukaryotes. RESULTS We present the de novo assembled genome (~ 4.75 Gbp with 85,849 protein-coding genes), transcriptome, proteome, and metabolome from Prorocentrum cordatum, a globally abundant, bloom-forming dinoflagellate. Using axenic algal cultures, we study the molecular mechanisms that underpin the algal response to heat stress, which is relevant to current ocean warming trends. We present the first evidence of a complementary interplay between RNA editing and exon usage that regulates the expression and functional diversity of biomolecules, reflected by reduction in photosynthesis, central metabolism, and protein synthesis. These results reveal genomic signatures and post-transcriptional regulation for the first time in a pelagic dinoflagellate. CONCLUSIONS Our multi-omics analyses uncover the molecular response to heat stress in an important bloom-forming algal species, which is driven by complex gene structures in a large, high-G+C genome, combined with multi-level transcriptional regulation. The dynamics and interplay of molecular regulatory mechanisms may explain in part how dinoflagellates diversified to become some of the most ecologically successful organisms on Earth.
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Affiliation(s)
- Katherine E Dougan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Zhi-Luo Deng
- Helmholtz-Center for Infection Research (HZI), Inhoffenstraße 7, Braunschweig, 38124, Germany
| | - Lars Wöhlbrand
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Carsten Reuse
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Boyke Bunk
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Yibi Chen
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Juliane Hartlich
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Karsten Hiller
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Uwe John
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
- Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstraße 231, 26129, Oldenburg, Germany
| | - Jana Kalvelage
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Johannes Mansky
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Meina Neumann-Schaal
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Jörg Overmann
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Jörn Petersen
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Selene Sanchez-Garcia
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Kerstin Schmidt-Hohagen
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Sarah Shah
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Cathrin Spröer
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Helena Sztajer
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Hui Wang
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Ralf Rabus
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Dieter Jahn
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Cheong Xin Chan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Irene Wagner-Döbler
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany.
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Hano T, Tomaru Y. Chronological age-related metabolome responses in the dinoflagellate Karenia mikimotoi, can predict future bloom demise. Commun Biol 2023; 6:273. [PMID: 36922623 PMCID: PMC10017670 DOI: 10.1038/s42003-023-04646-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 03/01/2023] [Indexed: 03/18/2023] Open
Abstract
Karenia mikimotoi is a common harmful algal bloom (HAB)-forming dinoflagellate and has caused severe financial loss in aquaculture. There are limited metabolomic studies on dinoflagellate biology. Here, we examined alterations in metabolic profiles over the growth curve of K. mikimotoi under nitrogen or phosphorus deficiency and further explored a key criterion for the diagnosis of late stationary phase to identify when the dinoflagellate cells will enter bloom demise. The results demonstrate the differential expression of metabolites for coping with chronological aging or nutrient deprivation. Furthermore, an increase in the glucose to glycine ratio in the late stationary phase was indicative of dinoflagellate cells entering bloom demise; this was also detected in the cultured diatom, Chaetoceros tenuissimus, indicating that this may be the general criterion for phytoplankton species. Our findings provide insights regarding chronological aging and the criterion for the prediction of phytoplankton bloom demise.
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Affiliation(s)
- Takeshi Hano
- Environment Conservation Division, Fisheries Technology Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, 739-0452, Japan.
| | - Yuji Tomaru
- Environment Conservation Division, Fisheries Technology Institute, National Research and Development Agency, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, 739-0452, Japan
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Mary L, Quere J, Latimier M, Rovillon GA, Hégaret H, Réveillon D, Le Gac M. Genetic association of toxin production in the dinoflagellate Alexandrium minutum. Microb Genom 2022; 8:mgen000879. [PMID: 36326655 PMCID: PMC9836089 DOI: 10.1099/mgen.0.000879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 07/25/2022] [Indexed: 11/06/2022] Open
Abstract
Dinoflagellates of the genus Alexandrium are responsible for harmful algal blooms and produce paralytic shellfish toxins (PSTs). Their very large and complex genomes make it challenging to identify the genes responsible for toxin synthesis. A family-based genomic association study was developed to determine the inheritance of toxin production in Alexandrium minutum and identify genomic regions linked to this production. We show that the ability to produce toxins is inheritable in a Mendelian way, while the heritability of the toxin profile is more complex. We developed the first dinoflagellate genetic linkage map. Using this map, several major results were obtained: 1. A genomic region related to the ability to produce toxins was identified. 2. This region does not contain any polymorphic sxt genes, known to be involved in toxin production in cyanobacteria. 3. The sxt genes, known to be present in a single cluster in cyanobacteria, are scattered on different linkage groups in A. minutum. 4. The expression of two sxt genes not assigned to any linkage group, sxtI and sxtG, may be regulated by the genomic region related to the ability to produce toxins. Our results provide new insights into the organization of toxicity-related genes in A. minutum, suggesting a dissociated genetic mechanism for the production of the different analogues and the ability to produce toxins. However, most of the newly identified genes remain unannotated. This study therefore proposes new candidate genes to be further explored to understand how dinoflagellates synthesize their toxins.
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Affiliation(s)
- Lou Mary
- Ifremer, DYNECO PELAGOS, 29280 Plouzané, France
- Ifremer, PHYTOX, Laboratoire METALG, F-44000 Nantes, France
- Laboratoire des Sciences de l’Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER - Institut Universitaire Européen de la Mer, 29280 Plouzané, France
| | | | | | | | - Hélène Hégaret
- Laboratoire des Sciences de l’Environnement Marin (LEMAR), UMR 6539 CNRS UBO IRD IFREMER - Institut Universitaire Européen de la Mer, 29280 Plouzané, France
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Marine Neurotoxins' Effects on Environmental and Human Health: An OMICS Overview. Mar Drugs 2021; 20:md20010018. [PMID: 35049872 PMCID: PMC8778346 DOI: 10.3390/md20010018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 12/27/2022] Open
Abstract
Harmful algal blooms (HAB), and the consequent release of toxic metabolites, can be responsible for seafood poisoning outbreaks. Marine wildlife can accumulate these toxins throughout the food chain, which presents a threat to consumers’ health. Some of these toxins, such as saxitoxin (STX), domoic acid (DA), ciguatoxin (CTX), brevetoxin (BTX), tetrodotoxin (TTX), and β-N-methylamino-L-alanine (BMAA), cause severe neurological symptoms in humans. Considerable information is missing, however, notably the consequences of toxin exposures on changes in gene expression, protein profile, and metabolic pathways. This information could lead to understanding the consequence of marine neurotoxin exposure in aquatic organisms and humans. Nevertheless, recent contributions to the knowledge of neurotoxins arise from OMICS-based research, such as genomics, transcriptomics, proteomics, and metabolomics. This review presents a comprehensive overview of the most recent research and of the available solutions to explore OMICS datasets in order to identify new features in terms of ecotoxicology, food safety, and human health. In addition, future perspectives in OMICS studies are discussed.
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Gao Y, Erdner DL. Dynamics of cell death across growth stages and the diel cycle in the dinoflagellate Karenia brevis. J Eukaryot Microbiol 2021; 69:e12874. [PMID: 34669235 DOI: 10.1111/jeu.12874] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent evidence suggests that programmed cell death (PCD) can play a role in stress-induced decline and termination of harmful algal blooms. However, components of the PCD cascade, i.e. reactive oxygen species (ROS) and caspase-like activity, have also been observed in the absence of exogenous stress, where their activities and functions remain unclear. Here, we characterized the variability of prevalence of cell death, ROS, and caspase-like activity at different growth phases and diel cycles in cultures of dinoflagellate Karenia brevis. Results show that ROS percentages increased with culture age and fluctuated in a phasing diel pattern, while caspase-like activity was observed throughout growth. In actively growing K. brevis cells, PCD components may be involved in key metabolic processes, while in stationary phase they may relate to stress acclimation. The circadian diel pattern of ROS may be explained by the balance between the metabolic generation of ROS and circadian rhythmicity of antioxidant enzymes. Overall, this work highlights not only the involvement of PCD components in the growth of marine phytoplankton, but the importance of understanding mechanisms controlling their accumulation, which would help to better interpret their presence in the field.
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Affiliation(s)
- Yida Gao
- Marine Science Institute, University of Texas at Austin, Port Aransas, Texas, USA
| | - Deana L Erdner
- Marine Science Institute, University of Texas at Austin, Port Aransas, Texas, USA
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Guo X, Wang Z, Liu L, Li Y. Transcriptome and metabolome analyses of cold and darkness-induced pellicle cysts of Scrippsiella trochoidea. BMC Genomics 2021; 22:526. [PMID: 34246248 PMCID: PMC8272339 DOI: 10.1186/s12864-021-07840-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 06/24/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Dinoflagellates are a group of unicellular organisms that are a major component of aquatic eukaryotes and important contributors to marine primary production. Nevertheless, many dinoflagellates are considered harmful algal bloom (HAB) species due to their detrimental environmental and human health impacts. Cyst formation is widely perceived as an adaptive strategy of cyst-forming dinoflagellates in response to adverse environmental conditions. Dinoflagellate cysts play critical roles in bloom dynamics. However, our insight into the underlying molecular basis of encystment is still limited. To investigate the molecular processes regulating encystment in dinoflagellates, transcriptome and metabolome investigations were performed on cold and darkness-induced pellicle cysts of Scrippsiella trochoidea. RESULTS No significant transcriptional response was observed at 2 h; however, massive transcriptome and metabolome reprogramming occurred at 5 h and in pellicle cysts. The gene-to-metabolite network demonstrated that the initial transformation from vegetative cells into pellicle cysts was highly energy demanding through the activation of catabolism, including glycolysis, β-oxidation, TCA cycle and oxidative phosphorylation, to cope with cold-darkness-induced stress. However, after transformation into pellicle cysts, the metabolism was greatly reduced, and various sugars, polyunsaturated fatty acids and amino acids accumulated to prolong survival. The identification of 56 differentially expressed genes (DEGs) related to signal transduction indicated that S. trochoidea received a cold-darkness signal that activated multiple signal transduction pathways, leading to encystment. The elevated expression of genes encoding enzymes involved in ROS stress suggested that pellicle cysts respond to increased oxidative stress. Several cell cycle-related genes were repressed. Intriguingly, 11 DEGs associated with sexual reproduction suggested that pellicle cysts (or some portion thereof) may be a product of sexual reproduction. CONCLUSIONS This study provides the first transcriptome and metabolome analyses conducted during the encystment of S. trochoidea, an event that requires complex regulatory mechanisms and impacts on population dynamics. The results reveal comprehensive molecular regulatory processes underlying life cycle regulation in dinoflagellates involving signal transduction, gene expression and metabolite profile, which will improve our ability to understand and monitor dinoflagellate blooms.
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Affiliation(s)
- Xin Guo
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, School of Life Science, South China Normal University, West 55 of Zhongshan Avenue, 510631, Guangzhou, China.,Department of Ecology, College of Life Science and Technology, Jinan University, West 601 of Huangpu Avenue, 510632, Guangzhou, China
| | - Zhaohui Wang
- Department of Ecology, College of Life Science and Technology, Jinan University, West 601 of Huangpu Avenue, 510632, Guangzhou, China.
| | - Lei Liu
- Department of Ecology, College of Life Science and Technology, Jinan University, West 601 of Huangpu Avenue, 510632, Guangzhou, China
| | - Yang Li
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, School of Life Science, South China Normal University, West 55 of Zhongshan Avenue, 510631, Guangzhou, China.
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7
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Cho Y, Hidema S, Omura T, Koike K, Koike K, Oikawa H, Konoki K, Oshima Y, Yotsu-Yamashita M. SxtA localizes to chloroplasts and changes to its 3'UTR may reduce toxin biosynthesis in non-toxic Alexandrium catenella (Group I) ✰. HARMFUL ALGAE 2021; 101:101972. [PMID: 33526188 DOI: 10.1016/j.hal.2020.101972] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/14/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
SxtA is the enzyme that catalyses the first step of saxitoxin biosynthesis. We developed an immunofluorescent method to detect SxtA using antibodies against SxtA peptides. Confocal microscopy revealed the presence of abundant, sub-cellularly localized signal in cells of toxic species and its absence in non-toxic species. Co-localization of SxtA with Rubisco II and ultra-structural observation by transmission electron microscopy strongly suggested the association of SxtA with chloroplasts. We also characterized a non-toxic sub-clone of Alexandrium catenella (Group I) to elucidate the mutation responsible for its loss of toxicity. Although sxtA4 gene copy number was indistinguishable in toxic and non-toxic sub-clones, mRNA and protein expression were significantly reduced in the non-toxic sub-clone and we uncovered sequence variation at the 3' untranslated region (3'UTR) of sxtA4 mRNA. We propose that differences in the sxtA4 mRNA 3'UTR lead to down-regulation of STX biosynthesis post-transcriptionally, thereby explaining the differences in toxicity amongst different A. catenella (Group I) sub-clones.
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Affiliation(s)
- Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan.
| | - Shizu Hidema
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University, 1 Hikariga-oka, Fukushima 960-1295, Japan
| | - Takuo Omura
- Laboratory of Aquatic Science Consultant Co., Ltd. 2-30-17, Higashikamata, Ota-ku, Tokyo 144-0031, Japan
| | - Kazuhiko Koike
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Kanae Koike
- Natural Science Center for Basic Research and Development, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Hiroshi Oikawa
- Japan Fisheries Research and Education Agency, Fisheries Technology Institute, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yasukatsu Oshima
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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Sprecher BN, Zhang H, Lin S. Nuclear Gene Transformation in the Dinoflagellate Oxyrrhis marina. Microorganisms 2020; 8:E126. [PMID: 31963386 PMCID: PMC7022241 DOI: 10.3390/microorganisms8010126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 11/16/2022] Open
Abstract
The lack of a robust gene transformation tool that allows proper expression of foreign genes and functional testing for the vast number of nuclear genes in dinoflagellates has greatly hampered our understanding of the fundamental biology in this ecologically important and evolutionarily unique lineage of microeukaryotes. Here, we report the development of a dinoflagellate expression vector containing various DNA elements from phylogenetically separate dinoflagellate lineages, an electroporation protocol, and successful expression of introduced genes in an early branching dinoflagellate, Oxyrrhis marina. This protocol, involving the use of Lonza's Nucleofector and a codon-optimized antibiotic resistance gene, has been successfully used to produce consistent results in several independent experiments for O. marina. It is anticipated that this protocol will be adaptable for other dinoflagellates and will allow characterization of many novel dinoflagellate genes.
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Affiliation(s)
| | - Huan Zhang
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Rd, Groton, CT 06340, USA;
| | - Senjie Lin
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Rd, Groton, CT 06340, USA;
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Wang X, Niu X, Chen Y, Sun Z, Han A, Lou X, Ge J, Li X, Yang Y, Jian J, Gonçalves RJ, Guan W. Transcriptome sequencing of a toxic dinoflagellate, Karenia mikimotoi subjected to stress from solar ultraviolet radiation. HARMFUL ALGAE 2019; 88:101640. [PMID: 31582153 DOI: 10.1016/j.hal.2019.101640] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
Solar ultraviolet radiation (UVR) is a stress factor in aquatic environments and may act directly or indirectly on orgnisms in the upper layers of the water column. However, UVR effects are usually species-specific and difficult to extrapolate. Here we use the HAB-forming, toxic dinoflagellate Karenia mikimotoi (which was found to be relatively resistant in previous studies) to investigate its transcriptional responses to a one-week UVR exposure. For this, batch cultures of K. mikimotoi were grown with and without UVR, and their transcriptomes (generated via RNAseq technology) were compared. RNA-seq generated 45.31 million reads, which were further assembled to 202600 unigenes (>300bp). Among these, ca. 61% were annotated with NCBI, NR, GO, KOG, PFAM, Swiss-Prot, and KEGG database. Transcriptomic analysis revealed 722 differentially expressed unigenes (DEGs, defined as being within a |log2 fold change| ≥ 2 and padj < 0.05) responding to solar UVR, which were only 0.36% of all unigenes. 716 unigenes were down-regulated, and only 6 unigenes were up-regulated in the UVR compared to non-UVR treatment. KEGG pathway further analysis revealed DEGs were involved in the different pathway; genes involved in the ribosome, endocytosis and steroid biosynthesis pathways were highly down-regulated, but this was not the case for those involved in the energy metabolisms (including photosynthesis, oxidative phosphorylation) which may contribute to the sustainable growth observed in UVR treatment. The up-regulated expression of both zinc-finger proteins (ZFPs) and ribosomal protein L11 (RPL11) may be one of the acclimated mechanisms against UVR. In addition, this work identified down-regulated genes involved in fatty acid degradation and the hydrophobic branched chain amino acids (e.g., Valine, leucine, and isoleucine), which act as structural components of cell membranes modulating lipid homeostasis or turnover. In conclusion, the present study suggests that the toxic dinoflagellate K. mikimotoi has limited transcriptomic regulation but confirms that it appears as a tolerant species in response to solar UVR. These findings expand current knowledge of gene expression in HAB-forming species in response to natural environment factors such as solar radiation.
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Affiliation(s)
- Xinjie Wang
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China; Marine Biology Institute, Shantou University, Shantou, Guangdong 515063 China
| | - Xiaoqin Niu
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Yiji Chen
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Zhewei Sun
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Axiang Han
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Xiayuan Lou
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Jingke Ge
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Xuanwen Li
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Yuqian Yang
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China
| | - Jianbo Jian
- Marine Biology Institute, Shantou University, Shantou, Guangdong 515063 China
| | - Rodrigo J Gonçalves
- Laboratorio de Oceanografía Biológica (LOBio), Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). U9120ACD, Puerto Madryn, Argentina
| | - Wanchun Guan
- Department of Marine Biotechnology, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang 325035 China.
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Omics Analysis for Dinoflagellates Biology Research. Microorganisms 2019; 7:microorganisms7090288. [PMID: 31450827 PMCID: PMC6780300 DOI: 10.3390/microorganisms7090288] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/20/2019] [Accepted: 08/21/2019] [Indexed: 01/13/2023] Open
Abstract
Dinoflagellates are important primary producers for marine ecosystems and are also responsible for certain essential components in human foods. However, they are also notorious for their ability to form harmful algal blooms, and cause shellfish poisoning. Although much work has been devoted to dinoflagellates in recent decades, our understanding of them at a molecular level is still limited owing to some of their challenging biological properties, such as large genome size, permanently condensed liquid-crystalline chromosomes, and the 10-fold lower ratio of protein to DNA than other eukaryotic species. In recent years, omics technologies, such as genomics, transcriptomics, proteomics, and metabolomics, have been applied to the study of marine dinoflagellates and have uncovered many new physiological and metabolic characteristics of dinoflagellates. In this article, we review recent application of omics technologies in revealing some of the unusual features of dinoflagellate genomes and molecular mechanisms relevant to their biology, including the mechanism of harmful algal bloom formations, toxin biosynthesis, symbiosis, lipid biosynthesis, as well as species identification and evolution. We also discuss the challenges and provide prospective further study directions and applications of dinoflagellates.
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Verma A, Barua A, Ruvindy R, Savela H, Ajani PA, Murray SA. The Genetic Basis of Toxin Biosynthesis in Dinoflagellates. Microorganisms 2019; 7:E222. [PMID: 31362398 PMCID: PMC6722697 DOI: 10.3390/microorganisms7080222] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/23/2019] [Accepted: 07/27/2019] [Indexed: 02/07/2023] Open
Abstract
In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth rates. One factor that may play a role in their ecological success is the production of complex secondary metabolite compounds that can have anti-predator, allelopathic, or other toxic effects on marine organisms, and also cause seafood poisoning in humans. Our knowledge about the genes involved in toxin biosynthesis in dinoflagellates is currently limited due to the complex genomic features of these organisms. Most recently, the sequencing of dinoflagellate transcriptomes has provided us with valuable insights into the biosynthesis of polyketide and alkaloid-based toxin molecules in dinoflagellate species. This review synthesizes the recent progress that has been made in understanding the evolution, biosynthetic pathways, and gene regulation in dinoflagellates with the aid of transcriptomic and other molecular genetic tools, and provides a pathway for future studies of dinoflagellates in this exciting omics era.
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Affiliation(s)
- Arjun Verma
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia.
| | - Abanti Barua
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
- Department of Microbiology, Noakhali Science and Technology University, Chittagong 3814, Bangladesh
| | - Rendy Ruvindy
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| | - Henna Savela
- Finnish Environment Institute, Marine Research Centre, 00790 Helsinki, Finland
| | - Penelope A Ajani
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
| | - Shauna A Murray
- Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia
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Wang H, Guo R, Ki JS. 6.0 K microarray reveals differential transcriptomic responses in the dinoflagellate Prorocentrum minimum exposed to polychlorinated biphenyl (PCB). CHEMOSPHERE 2018; 195:398-409. [PMID: 29274579 DOI: 10.1016/j.chemosphere.2017.12.066] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/23/2017] [Accepted: 12/11/2017] [Indexed: 06/07/2023]
Abstract
Endocrine disrupting chemicals (EDCs) have toxic effects on algae; however, their molecular genomic responses have not been sufficiently elucidated. Here, we evaluated genome-scaled responses of the dinoflagellate alga Prorocentrum minimum exposed to an EDC, polychlorinated biphenyl (PCB), using a 6.0 K microarray. Based on two-fold change cut-off, we identified that 609 genes (∼10.2%) responded to the PCB treatment. KEGG pathway analysis showed that differentially expressed genes (DEGs) were related to ribosomes, biosynthesis of amino acids, spliceosomes, and cellular processes. Many DEGs were involved in cell cycle progression, apoptosis, signal transduction, ion binding, and cellular transportation. In contrast, only a few genes related to photosynthesis and oxidative stress were expressed in response to PCB exposure. This was supported by that fact that there were no obvious changes in the photosynthetic efficiency and reactive oxygen species (ROS) production. These results suggest that PCB might not cause chloroplast and oxidative damage, but could lead to cell cycle arrest and apoptosis. In addition, various signal transduction and transport pathways might be disrupted in the cells, which could further contribute to cell death. These results expand the genomic understanding of the effects of EDCs on this dinoflagellate protist.
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Affiliation(s)
- Hui Wang
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Ruoyu Guo
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea.
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13
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Accoroni S, Tartaglione L, Dello Iacovo E, Pichierri S, Marini M, Campanelli A, Dell'Aversano C, Totti C. Influence of environmental factors on the toxin production of Ostreopsis cf. ovata during bloom events. MARINE POLLUTION BULLETIN 2017; 123:261-268. [PMID: 28863976 DOI: 10.1016/j.marpolbul.2017.08.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 08/16/2017] [Accepted: 08/19/2017] [Indexed: 06/07/2023]
Abstract
Intense blooms of the toxic dinoflagellate Ostreopsis have been a recurrent phenomenon along several Mediterranean coasts. Blooms have been associated with noxious effects on human health and mortality of marine organisms, due to the production of palytoxin-like compounds. We analyzed the toxin concentrations throughout an O. cf. ovata bloom to highlight their relationships with environmental parameters in the Conero Riviera, northern Adriatic Sea. High temperature and balanced nutrient conditions were the optimal environmental conditions to start and sustain blooms as well as to maximize toxin production. Ostreopsis showed a gradual decrease of toxin content throughout the bloom ascribed to the occurring of the same non-optimal conditions that led to the bloom decline. Moreover, our results suggest that toxin fraction released during bloom could be higher than that released in batch culture. Results from this study pointed out that the first bloom phase is potentially the most dangerous to human health.
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Affiliation(s)
- Stefano Accoroni
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
| | - Luciana Tartaglione
- Dipartimento di Farmacia, Scuola di Medicina, Università degli Studi di Napoli "Federico II", Via D. Montesano 49, 80131 Napoli, Italy
| | - Emma Dello Iacovo
- Dipartimento di Farmacia, Scuola di Medicina, Università degli Studi di Napoli "Federico II", Via D. Montesano 49, 80131 Napoli, Italy
| | - Salvatore Pichierri
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Mauro Marini
- Istituto di Scienze Marine (Consiglio Nazionale delle Ricerche), Largo Fiera della Pesca, 60125 Ancona, Italy
| | - Alessandra Campanelli
- Istituto di Scienze Marine (Consiglio Nazionale delle Ricerche), Largo Fiera della Pesca, 60125 Ancona, Italy
| | - Carmela Dell'Aversano
- Dipartimento di Farmacia, Scuola di Medicina, Università degli Studi di Napoli "Federico II", Via D. Montesano 49, 80131 Napoli, Italy
| | - Cecilia Totti
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
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14
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Haley ST, Alexander H, Juhl AR, Dyhrman ST. Transcriptional response of the harmful raphidophyte Heterosigma akashiwo to nitrate and phosphate stress. HARMFUL ALGAE 2017; 68:258-270. [PMID: 28962986 DOI: 10.1016/j.hal.2017.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 06/30/2017] [Accepted: 07/01/2017] [Indexed: 06/07/2023]
Abstract
The marine eukaryotic alga Heterosigma akashiwo (Raphidophyceae) is known for forming ichthyotoxic harmful algal blooms (HABs). In the past 50 years, H. akashiwo blooms have increased, occurring globally in highly eutrophic coastal and estuarine systems. These systems often incur dramatic physicochemical changes, including macronutrient (nitrogen and phosphorus) enrichment and depletion, on short timescales. Here, H. akashiwo cultures grown under nutrient replete, low N and low P growth conditions were examined for changes in biochemical and physiological characteristics in concert with transcriptome sequencing to provide a mechanistic perspective on the metabolic processes involved in responding to N and P stress. There was a marked difference in the overall transcriptional pattern between low N and low P transcriptomes. Both nutrient stresses led to significant changes in the abundance of thousands of contigs related to a wide diversity of metabolic pathways, with limited overlap between the transcriptomic responses to low N and low P. Enriched contigs under low N included many related to nitrogen metabolism, acquisition, and transport. In addition, metabolic modules like photosynthesis and carbohydrate metabolism changed significantly under low N, coincident with treatment-specific changes in photosynthetic efficiency and particulate carbohydrate content. P-specific contigs responsible for P transport and organic P use were more enriched in the low P treatment than in the replete control and low N treatment. These results provide new insight into the genetic mechanisms that distinguish how this HAB species responds to these two common nutrient stresses, and the results can inform future field studies, linking transcriptional patterns to the physiological ecology of H. akashiwo in situ.
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Affiliation(s)
- Sheean T Haley
- Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY, USA
| | - Harriet Alexander
- Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Andrew R Juhl
- Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY, USA; Columbia University, Department of Earth and Environmental Sciences, Palisades, NY, USA
| | - Sonya T Dyhrman
- Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY, USA; Columbia University, Department of Earth and Environmental Sciences, Palisades, NY, USA.
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15
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Jang SH, Jeong HJ, Chon JK, Lee SY. De novo assembly and characterization of the transcriptome of the newly described dinoflagellate Ansanella granifera: Spotlight on flagellum-associated genes. Mar Genomics 2017; 33:47-55. [PMID: 28111206 DOI: 10.1016/j.margen.2017.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/11/2017] [Accepted: 01/11/2017] [Indexed: 11/15/2022]
Abstract
Many dinoflagellates are known to cause red tides and often outgrow non-motile diatoms and motile small flagellates through active vertical migration between well-lit surface and eutrophic deep waters and/or by locating and ingesting prey cells. Their flagella play important roles in these two critical behaviors. However, the structural and functional genes of dinoflagellate flagella are very little known. Thus, a de novo assembly and characterization of the transcriptome of the fast-swimming dinoflagellate Ansanella granifera were conducted and its flagellum genes were compared with those of other dinoflagellates, motile small flagellates, and non-motile protist species. Based on assembled data using Trinity/CLC combined strategy, 83,652 transcripts of A. granifera were identified. The assembled consensus sequences were annotated to the NCBI non-redundant (nr), InterProScan, Gene Ontology (GO), and KEGG pathway analyses. Moreover, 71 structural and 35 functional flagellum-associated genes expressed were identified. The number of expressed flagellar structural and functional genes of A. granifera was not markedly different from those of other dinoflagellates or motile small flagellates, but much greater than those of non-motile species. Furthermore, in both phylogenetic trees based on the outer dynein arm (ODA1, ODA9, and DLC1) and inner dynein arm (IDA4, IDA7, and BOP5) flagellum genes of dinoflagellates, the problem of the long-branch attraction artifacts of Oxyrrhis marina which has been reported in the phylogenetic trees based on ribosomal DNA was removed. Moreover, in both phylogenetic trees based on the ODA and IDA flagellum genes, the species in the order Peridiniales or Gymnodiniales were revealed to belong to a big clade of each order. Therefore, the phylogenetic tree based on the flagellum genes is likely to give a clue to resolve the problem of separation in a big clade of a dinoflagellate order which has also been reported in the phylogenetic trees based on ribosomal DNA.
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Affiliation(s)
- Se Hyeon Jang
- School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Hae Jin Jeong
- School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea; Advanced Institutes of Convergence Technology, Suwon, Gyeonggi-do 16229, Republic of Korea.
| | - Jae Kyung Chon
- Department of Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung Yeon Lee
- School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
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16
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Guo R, Lim WA, Ki JS. Genome-wide analysis of transcription and photosynthesis inhibition in the harmful dinoflagellate Prorocentrum minimum in response to the biocide copper sulfate. HARMFUL ALGAE 2016; 57:27-38. [PMID: 30170719 DOI: 10.1016/j.hal.2016.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 06/08/2023]
Abstract
Copper is an essential trace metal for organisms; however, excess copper may damage cellular processes. Their efficiency and physiological effects of biocides have been well documented; however, molecular transcriptome responses to biocides are insufficiently studied. In the present study, a 6.0K oligonucleotide chip was developed to investigate the molecular responses of the harmful dinoflagellate Prorocentrum minimum to copper sulfate (CuSO4) treatment. The results revealed that 515 genes (approximately 8.6%) responded to CuSO4, defined as being within a 2-fold change. Further, KEGG pathway analysis showed that differentially expressed genes (DEGs) were involved in ribosomal function, RNA transport, carbon metabolism, biosynthesis of amino acids, photosystem maintenance, and other cellular processes. Among the DEGs, 49 genes were related to chloroplasts and mitochondria. Furthermore, the genes involved in the RAS signaling pathway, MAPK signaling pathway, and transport pathways were identified. An additional experiment showed that the photosynthesis efficiency decreased considerably, and reactive oxygen species (ROS) production increased in P. minimum after CuSO4 exposure. These results suggest that CuSO4 caused cellular oxidative stress in P. minimum, affecting the ribosome and mitochondria, and severely damaged the photosystem. These effects may potentially lead to cell death, although the dinoflagellate has developed a complex signal transduction process to combat copper toxicity.
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Affiliation(s)
- Ruoyu Guo
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, Republic of Korea
| | - Weol-Ae Lim
- Oceanic Climate & Ecology Research Division, the National Institute of Fisheries Science (NISF), Busan 46083, Republic of Korea
| | - Jang-Seu Ki
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 03016, Republic of Korea.
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17
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Guo R, Wang H, Suh YS, Ki JS. Transcriptomic profiles reveal the genome-wide responses of the harmful dinoflagellate Cochlodinium polykrikoides when exposed to the algicide copper sulfate. BMC Genomics 2016; 17:29. [PMID: 26732698 PMCID: PMC4702327 DOI: 10.1186/s12864-015-2341-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 12/22/2015] [Indexed: 11/29/2022] Open
Abstract
Background Harmful algal blooms (HABs) caused by the dinoflagellate Cochlodinium polykrikoides lead to severe environmental impacts in oceans worldwide followed by huge economic losses. Algicide agent copper sulfate (CuSO4) is regard as an economical and effective agent for HABs mitigation; its biochemical and physiological effects were revealed in C. polykrikoides. However, molecular mechanisms of CuSO4 effect on the C. polykrikoides, even other HAB species, have not been investigated. The present study investigated the transcriptional response of C. polykrikoides against CuSO4 treatments, with the aim of providing certain molecular mechanism of CuSO4 effect on the C. polykrikoides blooms. Results RNA-seq generated 173 million reads, which were further assembled to 191,212 contigs. 43.3 %, 33.9 %, and 15.6 % of contigs were annotated with NCBI NR, GO, and KEGG database, respectively. Transcriptomic analysis revealed 20.6 % differential expressed contigs, which grouped into 8 clusters according to K-means clustering analysis, responding to CuSO4; 848 contigs were up-regulated and 746 contigs were down-regulated more than 2-fold changes from 12 h to 48 h exposure. KEGG pathway analysis of eukaryotic homologous genes revealed the differentially expressed genes (DEGs) were involved in diverse pathway; amongst, the genes involved in the translation, spliceosome, and/or signal transduction genes were highly regulated. Most of photosystem related genes were down-regulated and most of mitochondria related genes were up-regulated. In addition, the genes involved in the copper ion binding or transporting and antioxidant systems were identified. Measurement of chlorophyll fluorescence showed that photosynthesis was significantly inhibited by CuSO4 exposure. Conclusions This study reported the first transcriptome of the C. polykrikoides. The widely differential expressed photosystem genes suggested photosynthetic machinery were severely affected, and may further contribute to the cell death. Furthermore, gene translation and transcription processes may be disrupted, inhibiting cell growth and proliferation, and possibly accelerating cell death. However, antioxidant systems resistant to CuSO4 caused stress; mitochondrion may compensate for photosynthesis efficiency decreasing caused energy deficiency. In addition, various signal transduction pathways may be involved in the CuSO4 induced regulation network in the C. polykrikoides. These data provide the potential transcriptomic mechanism to explain the algicide CuSO4 effect on the harmful dinoflagellate C. polykrikoides. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2341-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ruoyu Guo
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul, 110-743, Korea.
| | - Hui Wang
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul, 110-743, Korea
| | - Young Sang Suh
- Fishery and Ocean Information Division, National Fisheries Research & Development Institute, Busan, 619-705, Korea.
| | - Jang-Seu Ki
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul, 110-743, Korea.
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Kimura K, Okuda S, Nakayama K, Shikata T, Takahashi F, Yamaguchi H, Skamoto S, Yamaguchi M, Tomaru Y. RNA Sequencing Revealed Numerous Polyketide Synthase Genes in the Harmful Dinoflagellate Karenia mikimotoi. PLoS One 2015; 10:e0142731. [PMID: 26561394 PMCID: PMC4641656 DOI: 10.1371/journal.pone.0142731] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 10/26/2015] [Indexed: 12/03/2022] Open
Abstract
The dinoflagellate Karenia mikimotoi forms blooms in the coastal waters of temperate regions and occasionally causes massive fish and invertebrate mortality. This study aimed to elucidate the toxic effect of K. mikimotoi on marine organisms by using the genomics approach; RNA-sequence libraries were constructed, and data were analyzed to identify toxin-related genes. Next-generation sequencing produced 153,406 transcript contigs from the axenic culture of K. mikimotoi. BLASTX analysis against all assembled contigs revealed that 208 contigs were polyketide synthase (PKS) sequences. Thus, K. mikimotoi was thought to have several genes encoding PKS metabolites and to likely produce toxin-like polyketide molecules. Of all the sequences, approximately 30 encoded eight PKS genes, which were remarkably similar to those of Karenia brevis. Our phylogenetic analyses showed that these genes belonged to a new group of PKS type-I genes. Phylogenetic and active domain analyses showed that the amino acid sequence of four among eight Karenia PKS genes was not similar to any of the reported PKS genes. These PKS genes might possibly be associated with the synthesis of polyketide toxins produced by Karenia species. Further, a homology search revealed 10 contigs that were similar to a toxin gene responsible for the synthesis of saxitoxin (sxtA) in the toxic dinoflagellate Alexandrium fundyense. These contigs encoded A1-A3 domains of sxtA genes. Thus, this study identified some transcripts in K. mikimotoi that might be associated with several putative toxin-related genes. The findings of this study might help understand the mechanism of toxicity of K. mikimotoi and other dinoflagellates.
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Affiliation(s)
- Kei Kimura
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, Japan
- Research Fellow of the Japan Society for the Promotion of Science, Kojimachi Business Center Building, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo, Japan
| | - Shujiro Okuda
- Niigata University Graduate School of Medical and Dental Sciences, 1–757 Asahimachi-dori, Chuo-ku, Niigata, Japan
| | - Kei Nakayama
- Center for Marine Environmental Studies (CMES), Ehime University, 2–5 Bunkyo-cho, Matsuyama, Ehime, Japan
| | - Tomoyuki Shikata
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, Japan
| | - Fumio Takahashi
- Department of Biotechnology, College of Life Sciences, Rhitsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga, Japan
| | - Haruo Yamaguchi
- Laboratory of Aquatic Environmental Science, Faculty of Agriculture, Kochi University, 200, Monobe, Nankoku, Kochi, Japan
| | - Setsuko Skamoto
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, Japan
| | - Mineo Yamaguchi
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, Japan
| | - Yuji Tomaru
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima, Japan
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Alvarez M, Schrey AW, Richards CL. Ten years of transcriptomics in wild populations: what have we learned about their ecology and evolution? Mol Ecol 2015; 24:710-25. [PMID: 25604587 DOI: 10.1111/mec.13055] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 12/16/2014] [Accepted: 12/18/2014] [Indexed: 12/13/2022]
Abstract
Molecular ecology has moved beyond the use of a relatively small number of markers, often noncoding, and it is now possible to use whole-genome measures of gene expression with microarrays and RNAseq (i.e. transcriptomics) to capture molecular response to environmental challenges. While transcriptome studies are shedding light on the mechanistic basis of traits as complex as personality or physiological response to catastrophic events, these approaches are still challenging because of the required technical expertise, difficulties with analysis and cost. Still, we found that in the last 10 years, 575 studies used microarrays or RNAseq in ecology. These studies broadly address three questions that reflect the progression of the field: (i) How much variation in gene expression is there and how is it structured? (ii) How do environmental stimuli affect gene expression? (iii) How does gene expression affect phenotype? We discuss technical aspects of RNAseq and microarray technology, and a framework that leverages the advantages of both. Further, we highlight future directions of research, particularly related to moving beyond correlation and the development of additional annotation resources. Measuring gene expression across an array of taxa in ecological settings promises to enrich our understanding of ecology and genome function.
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Affiliation(s)
- Mariano Alvarez
- Department of Integrative Biology, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL, 33620, USA
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20
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Van Dolah FM, Zippay ML, Pezzolesi L, Rein KS, Johnson JG, Morey JS, Wang Z, Pistocchi R. Subcellular localization of dinoflagellate polyketide synthases and fatty acid synthase activity. JOURNAL OF PHYCOLOGY 2013; 49:1118-1127. [PMID: 27007632 DOI: 10.1111/jpy.12120] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/25/2013] [Indexed: 06/05/2023]
Abstract
Dinoflagellates are prolific producers of polyketide secondary metabolites. Dinoflagellate polyketide synthases (PKSs) have sequence similarity to Type I PKSs, megasynthases that encode all catalytic domains on a single polypeptide. However, in dinoflagellate PKSs identified to date, each catalytic domain resides on a separate transcript, suggesting multiprotein complexes similar to Type II PKSs. Here, we provide evidence through coimmunoprecipitation that single-domain ketosynthase and ketoreductase proteins interact, suggesting a predicted multiprotein complex. In Karenia brevis (C.C. Davis) Gert Hansen & Ø. Moestrup, previously observed chloroplast localization of PKSs suggested that brevetoxin biosynthesis may take place in the chloroplast. Here, we report that PKSs are present in both cytosol and chloroplast. Furthermore, brevetoxin is not present in isolated chloroplasts, raising the question of what chloroplast-localized PKS enzymes might be doing. Antibodies to K. brevis PKSs recognize cytosolic and chloroplast proteins in Ostreopsis cf. ovata Fukuyo, and Coolia monotis Meunier, which produce different suites of polyketide toxins, suggesting that these PKSs may share common pathways. Since PKSs are closely related to fatty acid synthases (FAS), we sought to determine if fatty acid biosynthesis colocalizes with either chloroplast or cytosolic PKSs. [(3) H]acetate labeling showed fatty acids are synthesized in the cytosol, with little incorporation in chloroplasts, consistent with a Type I FAS system. However, although 29 sequences in a K. brevis expressed sequence tag database have similarity (BLASTx e-value <10(-10) ) to PKSs, no transcripts for either Type I (cytosolic) or Type II (chloroplast) FAS are present. Further characterization of the FAS complexes may help to elucidate the functions of the PKS enzymes identified in dinoflagellates.
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Affiliation(s)
- Frances M Van Dolah
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
- Marine Biomedical and Environmental Sciences, Medical University of South Carolina, Charleston, South Carolina, 29412, USA
| | - Mackenzie L Zippay
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
- Marine Biomedical and Environmental Sciences, Medical University of South Carolina, Charleston, South Carolina, 29412, USA
| | - Laura Pezzolesi
- Interdepartmental Research Centre for Environmental Science (CIRSA), University of Bologna, Ravenna, 48123, Italy
| | - Kathleen S Rein
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
| | - Jillian G Johnson
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
- Marine Biomedical and Environmental Sciences, Medical University of South Carolina, Charleston, South Carolina, 29412, USA
| | - Jeanine S Morey
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
| | - Zhihong Wang
- Marine Biotoxins Program, NOAA Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina, 29412, USA
| | - Rossella Pistocchi
- Interdepartmental Research Centre for Environmental Science (CIRSA), University of Bologna, Ravenna, 48123, Italy
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Transcription and Maturation of mRNA in Dinoflagellates. Microorganisms 2013; 1:71-99. [PMID: 27694765 PMCID: PMC5029490 DOI: 10.3390/microorganisms1010071] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/10/2013] [Accepted: 10/14/2013] [Indexed: 01/17/2023] Open
Abstract
Dinoflagellates are of great importance to the marine ecosystem, yet scant details of how gene expression is regulated at the transcriptional level are available. Transcription is of interest in the context of the chromatin structure in the dinoflagellates as it shows many differences from more typical eukaryotic cells. Here we canvas recent transcriptome profiles to identify the molecular building blocks available for the construction of the transcriptional machinery and contrast these with those used by other systems. Dinoflagellates display a clear paucity of specific transcription factors, although surprisingly, the rest of the basic transcriptional machinery is not markedly different from what is found in the close relatives to the dinoflagellates.
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22
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Global analysis of mRNA half-lives and de novo transcription in a dinoflagellate, Karenia brevis. PLoS One 2013; 8:e66347. [PMID: 23776661 PMCID: PMC3679056 DOI: 10.1371/journal.pone.0066347] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 05/06/2013] [Indexed: 12/24/2022] Open
Abstract
Dinoflagellates possess many physiological processes that appear to be under post-transcriptional control. However, the extent to which their genes are regulated post-transcriptionally remains unresolved. To gain insight into the roles of differential mRNA stability and de novo transcription in dinoflagellates, we biosynthetically labeled RNA with 4-thiouracil to isolate newly transcribed and pre-existing RNA pools in Karenia brevis. These isolated fractions were then used for analysis of global mRNA stability and de novo transcription by hybridization to a K. brevis microarray. Global K. brevis mRNA half-lives were calculated from the ratio of newly transcribed to pre-existing RNA for 7086 array features using the online software HALO (Half-life Organizer). Overall, mRNA half-lives were substantially longer than reported in other organisms studied at the global level, ranging from 42 minutes to greater than 144 h, with a median of 33 hours. Consistent with well-documented trends observed in other organisms, housekeeping processes, including energy metabolism and transport, were significantly enriched in the most highly stable messages. Shorter-lived transcripts included a higher proportion of transcriptional regulation, stress response, and other response/regulatory processes. One such family of proteins involved in post-transcriptional regulation in chloroplasts and mitochondria, the pentatricopeptide repeat (PPR) proteins, had dramatically shorter half-lives when compared to the arrayed transcriptome. As transcript abundances for PPR proteins were previously observed to rapidly increase in response to nutrient addition, we queried the newly synthesized RNA pools at 1 and 4 h following nitrate addition to N-depleted cultures. Transcriptome-wide there was little evidence of increases in the rate of de novo transcription during the first 4 h, relative to that in N-depleted cells, and no evidence for increased PPR protein transcription. These results lend support to the growing consensus of post-transcriptional control of gene expression in dinoflagellates.
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